98 astro starting issues

It will start fine the first time after sitting for a few hours, but if I turn it off and try to restart it won't unless I push the gas pedal to the floor. Changed fuel pump and filter because it had low fuel pressure. That didn't help. Also changed the fuel pressure regulator ( which was a giant pain. ) That didn't help either. I gave it a tune up about 130,000 miles when it had no issues at all. The van now has 150,000 + on it. My mechanic suggests I stop throwing money into it. Any thoughts?????

When you hold the pedal to the floor and try to start the engine, the ECM disables the injectors. If it starts like this, you most likely have a fuel leak in the plenum. It could be a leaky fuel injector or an O ring leaking inside the plenum. The ECM does not directly monitor the injectors so the check engine light may or may not come on. The easy way to confirm a leak is to do a fuel pressure and leakdown test. Key ON, engine OFF and cold, fuel pump running, fuel pressure must be 60psi to 66psi and must remain above 55psi for 3 to 5 minutes after the fuel pump shuts off. Post your results.

Ended up being the engine coolant temp. sensor. 20$ part just below the thermostat housing. That threw a check engine light about 2 months ago along with a Mass Air Flow code, but this starting problem didn't start until about a month ago. Changed the Mass Air Flow Sensor but not the coolant temp. sensor. Didn't throw another check engine code so I kinda forgot about it. I talked to a teacher at Lincon Tech and he told me to change that. It did the trick. Now it starts like and champ every time. I did the fuel pressure leak test it it was good. Thanks for the info.

Kevin